Unit 1 Art 你听说过《蒙娜丽莎》吗?知道它是谁的名作吗?让我们一起来了解一下吧!She is widely seen as proof that good looks can last forever. But, at over 500 years of age, time is catching up with Mona Lisa .The health of the famous picture, painted by Leonardo da Vinci (列奥纳多·达 · 芬 奇 ) during 1503—1506, is getting worse by the year, according to the Louvre Museum (卢浮宫博物馆) where it is housed. “The thin, wooden panel (嵌板) on which Mona Lisa is painted in oil has changed shape since experts checked it two years ago , ” the museum said. Visitors have noticed the change but repairing the world's most famous painting is not easy. Experts are not sure about the materials the Italian artist used and their current chemical state.Nearly six million people go to see Mona Lisa every year, and many are attracted by the mystery of her smile. “It is very interesting that when you're not looking at her, she seems to be smiling, and then you look at her and she stops , ” said Professor Margaret Livingstone of Harvard University. “It's because direct vision is excellent at picking up details, but less suited to look at shadows. Da Vinci painted the smile in shadows.”However, the actual history of Mona Lisa is just as mysterious as the smile. Da Vinci himself loved it so much that he always carried it with him, until it was eventually sold to France's King Francis Ⅰ in 1168.In 1911, the painting was stolen from the Louvre by a former employee, who took it out of the museum hidden under his coat. He said he planned to return it to Italy. The painting was sent back to France two years later.During World War Ⅱ, French hid the painting in small towns to keep it out of...